1. Field of the Invention
Example embodiments of the present invention relate in general to methods of configuring a cell in a wireless communication network.
2. Description of the Related Art
A wireless network generally is divided into a multiplicity of cells with each cell having at least one base station. A user within the cell wishing to send information establishes communication with a base station in the cell. This receiving base station communicates typically with a mobile switching center, another base station or other network entity that, in turn, relays the information through the network to another base station or network, e.g., a public switch telephone network or the internet, where the intended recipient is located.
The efficient use of network resources requires a multiplexing scheme in which communication from numerous users (often as many as 200 users per cell) are being handled simultaneously. Similarly, each mobile at times receives a decodable signal from more than one base station (typically 3, sometimes 6 or more). A variety of protocols has been developed to achieve such goals. Generally, in accordance with the protocol being employed, identification and operation parameters are assigned to each base station and to each user.
A base station identifies itself by transmitting on the pilot channel with a pseudo random noise (PN) pattern beginning at an assigned PN offset. Users wishing to initiate communication search for a signal on a pilot channel and identify a base station for communication by the PN offset of the sensed pilot channel transmission. Other protocols such as universal mobile telecommunication systems (UTMS) have their own identification parameters such as scrambling codes.
Various parameters, in addition to identification parameters, are also an essential part of network management. Within any discrete geographic region the base stations present are assigned a limited number of carrier frequencies. A suitable choice of other parameters is also important. For example, the transmission intensity of a base station or of an individual user often can have a profound effect on the interference generated for other base stations or users who are not the intended receiver of the transmission, and on the probability of transmission reception by the intended receiver. A variety of other operating parameters such as antenna orientation, hand-off thresholds, traffic power limits and pilot power fraction of total amplifier power can affect network function.
In establishing a communications network, various parameters are set for each base station, often numbering as many as 1000 base stations for a metropolitan area. Thus, significant planning and configuration associated with these parameters typically precede the establishment of the network. Although at least some of these parameters can be adjusted as the network evolves, the incipient choices are carefully made to avoid network failure or to avoid an excessive duration and/or area of unacceptable operation.
Even after a network is operating, additional base stations can be added as the network expands. Moreover, due to changes in the network, one or more parameters of an existing base station in the network may need to be adjusted. These additional or existing base stations have various parameters that may thus require configuration or adjustment. A poor choice of parameters to set for initial operation or to adjust during operation due to a network change has the potential for causing network failure and/or unacceptable degradation in network efficiency or resources.
The efforts and concomitant costs associated with planning, configuring, adjusting and/or expanding a network are substantial. Significantly, there is an accelerating growth trend in the number and density of cells in wireless networks. Accordingly, the fraction of revenues service providers expend on to configure and plan their networks is expected to grow. The situation may be further aggravated as demand for higher bandwidth services increases and as wireless data and voice services become ubiquitous.
Traditionally, each time new equipment such as a cell is added to the network, or an existing cell requires a change to one or more parameters due to a change in the network, the new or existing equipment must be manually configured. The configuration of other network entities (other cells, MSC or other centralized controller) must also be adjusted to account for this new equipment. This manual process typically requires multiple changes and is expensive to implement (in part due to the requirement for human intervention).
This time and cost problem is getting worse as networks develop and evolve. For example, changes in usage patterns and services are forcing networks to have more cells that are spaced closer together. This is particularly being driven by (a) the desire to have in-building coverage means more cells covering less territory, and (b) the attempts made to provide high speed data coverage over larger areas. In order to obtain these high speeds, improved signal to noise ratios are needed, which limits the geographic distance between the user and the cell. Service providers are thus increasingly being required to install more cells closer to each other.
As a consequence, installation and maintenance costs are becoming a larger fraction of the service provider's expenditures. If not reduced or controlled, these costs can limit investment for new services. Moreover, the potential for mistaken configuration rises as the network complexity increases with the number of cells in the network. Erroneous configuration of a cell is more likely where substantial human intervention is required.